古湖洪水可能雕刻出大峡谷

Mineral grains show Colorado River filled a basin at the canyon’s head millions of years ago PAUL VOOSEN I t’s a debate that seems nearly as old as its subject: How did the Grand Canyon, that most charismatic of megalandscapes, come to be? Geological Survey. “The lake must have played a major role in the forma- tion of the Grand Canyon.” Rebecca Flowers, a geochronologist at the University of Colorado (CU) Boulder, says Crow and his colleagues “make a reasonable case that lake spillover can explain the data,” but it’s still possible the water took a different route. …